Wheelchairs in the modern form have been around since at least 1760, when John Joseph Merlin invented pushrim propulsion. The Merlin Chair, as it was called, bears a remarkable resemblance to wheelchairs today, despite the intervening 250 years. The conventional pushrim operated wheelchair has become the prevalent assistive care mobility device because of its simplicity, low cost, and intuitive operation. However, there i a cost for these advantages, as the kinematic design leaves much to be desired, causing a high incidence of injuries and pain over time. Ramps and inclines are ubiquitous in the world. Ascending a ramp with a conventional pushrim wheelchair requires a push-and-grab propulsion technique which results in increased forces being repetitively imposed on the arms and shoulders. These forces result in increased incidence of injuries. Additionally, if the manual wheelchair has strength or coordination challenges, negotiating ramps can be especially difficult and dangerous, with the possibility of crashes and falling. The wheelchair anti-rollback device addresses these injury and safety issues with a simple, innovative mechanism which has selectable anti-rollback and free-wheeling modes. The mechanism also allows complete maneuverability, including backward propelling, while in anti-rollback mode. The premise of the study is that the use of the device will decrease the incidence and severity of user reported pain. An electronic use monitor will record frequency of use data. Multiple prototype devices will allow both in-lab testing and an in-home field trial. Data collected will include push dynamics and user outcomes measures allowing correlation of the operation of the device with user reported pain.